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Joined 1 year ago
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Cake day: September 1st, 2023

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  • Losing weight and not sleeping face up may help in any case.

    If you usually feel tired or sleepy during the day, it could be sleep apnea, which can have long term negative effects on your health. In that case, see a doctor, who will usually perform tests while you sleep and then may prescribe CPAP. If that doesn’t work or you find it too uncomfortable and the apnea is severe, you may be offered surgery.

    There are some commercial devices that might help. Nasal strips are an option if you suspect your nasal passages could be compromised (deviated nasal septum). Chin straps and other devices that position your jaw do help in some cases wherein the issue is in your throat, especially when combined with CPAP.

    Edit: also, don’t take medical advice from people on the internet ;)





  • Thank you! :)

    I managed to get 4 piezo elements to work, limited by the FPGA. This was actually enough for some reasonable horizontal resolution since I used a phase array configuration, so the downside was the electronics had to generate very precisely timed pulses. The fourth prototype had 10 working elements thanks to replacing the MCU-FPGA duo with just a more powerful FPGA and using conductive glue to more reliably connect the elements themselves.

    It was configurable to use any even divisor of 120 MHz, but in practice anything over 1 MHz would not even make it out of the acoustic lens due to the low voltage and low quality impedance matching layer. And much lower frequencies are barely useful anyways, so the true working range was narrow.

    For the acoustic lens, I used the parametric design software OpenSCAD, with an equation for aberration-free lenses I had found somewhere and saved long before (will find it if you want) and the speed of sound in the different materials.



  • Of course!

    I wanted to test whether a cheap piezo buzzer could be used as a crude ultrasound probe. It worked, so I tried to upgrade it into full-blown ultrasound imaging. The third iteration of that did produce an image, using a piezo buzzer cut in sections, a cheap FPGA, a MCU, custom PCB and mostly 3D printed pieces (acoustic lens, etc.). Aside from the expected low resolution, turned out that it wouldn’t image anything beyond about 1 cm.

    I did make a fourth iteration of the device, much smaller and theoretically much better. But life happened and I never finished the coding part.